Electric arc welders are employed to weld metals together by using a power source to pass a current between an electrode and a workpiece. In some applications, the electrode is a continuous wire drawn from a drum or reel, which is advanced through a contact tip, melted and deposited onto the workpiece. Wire feeders are often used to advance the wire, preferably in a consistent and controllable manner, to the contact tip for use in the welding operation. Wire feeders can be manufactured in several forms, each optimized for a specific application.
In certain electric arc welding operations, a short circuit welding process is employed that includes an arc state and a short circuit state in each of a plurality of low frequency welding cycles. The power supplied to a welding electrode in this process is controlled according to a detected short circuit state to accurately control heat and reduce weld spatter. To facilitate transition between the arc state and the short circuit state, a wire feeder that allows both advancement and retraction of wire can be used to enhance the short circuit welding process. In operation, the short circuit state is entered by advancing the wire until the wire touches the weld pool. The arc state is entered by retracting the wire until the wire does not touch the weld pool, wherein an arc is formed.
To be effective, wire direction must be reversed within an abbreviated window of time, such as 5-10 milliseconds. Due to the inertia of conventional wire feeders, however, wire manipulation within this short window of time is difficult, if not impossible. Previous solutions using stepper or servo motors have proven ineffective as coordination of output is overly complex and/or may not meet necessary physical demands over a long time period. In view of these deficiencies, systems and methods are needed to minimize inertia of wire feeders to facilitate long term implementation thereof.